* {
  margin: 0;
  padding: 0;
}
body,
html {
  width: 100%;
  height: 100%;
}
a {
  text-decoration: none;
}
body {
  background-image: linear-gradient(45deg, red, green);
}

div.outer {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}
div#clock {
  font-size: 4em;
  color: white;
  text-align: center;
  border-radius: 10px;
  padding: 20px;
  background-color: rgba(0, 0, 0, 0.5);
  box-shadow: 0 0 20px black;
  z-index: 100;
  user-select: none;
  cursor: default;
}
div.outer div.gitee {
  width: 100%;
  /* height: 100px; */
  height: 0;
  overflow: hidden;
  text-align: center;
  font-size: 4em;
  /* margin-bottom: 10%; */
  transition: all 0.5s;
}
div.outer div.gitee a {
  width: 100%;
  height: 100%;
  display: block;
  color: rgba(135, 0, 224, 0.603);
  text-decoration: none;
  cursor: default;
}
div.outer:hover div.gitee {
  height: 100px;
  margin-bottom: 10%;
  background-color: rgba(0, 0, 0, 0.5);
  box-shadow: 0 0 20px black;
}
.clock {
  width: 200px;
  height: 200px;
  border: 5px solid black;
  border-radius: 50%;
  position: relative;
  margin: 50px auto;
}

.hand {
  width: 50%;
  height: 2px;
  background: black;
  position: absolute;
  top: 50%;
  left: 50%;
  transform-origin: 100%;
  transform: translate(-50%, -50%) rotate(90deg);
  transition: transform 0.05s;
}

.hour-hand {
  background: rgb(65, 42, 165);
  width: 25%;
}

.minute-hand {
  background: gray;
  width: 38%;
}

.second-hand {
  background: red;
  width: 45%;
}

.cul {
  width: 100%;
  /* height: 100px; */
  height: 0;
  overflow: hidden;
  text-align: center;
  font-size: 4em;
  /* margin-bottom: 10%; */
  transition: all 0.5s;
  overflow: hidden;
}
.cul iframe{
    height: 320px;
}
div.outer:hover .cul {
  height: 320px;
  margin-top: 10%;
  background-color: rgba(0, 0, 0, 0.5);
  box-shadow: 0 0 20px black;
}
